JSON to TypeScript

What this Json To Typescript does

This English-language tool converts any valid JSON object or array into ready-to-use TypeScript interfaces in seconds. Paste a response from an API, a config file, or a fixture, and the tool infers a full typescript json type tree — including nested objects, arrays, and union types. Optional fields are detected automatically by comparing keys across all elements in heterogeneous arrays, so you don't spend time hand-editing every ? after the fact. Most free converters (json2ts included) mark every field as required and leave cleanup to you. Here, that detection is built in. 100% client-side — your data never leaves your browser. No uploads, no tracking, no server logs. JSON was first specified by Douglas Crockford in 2001, and the format's simplicity is precisely why it became the default wire format for REST and GraphQL alike — making accurate type inference a daily need for TypeScript developers.

Features

• Recursive type inference. Handles deeply nested JSON structures and generates a correct typescript json schema for every level of nesting, not just the top-level keys.
• Optional-field detection. Scans all elements in a JSON array and marks fields that don't appear in every element as optional (?), saving manual cleanup after generation.
• Configurable root type name. Set your own name for the root interface before generating — no more renaming RootObject by hand across your codebase.
• Works with tsconfig-aware projects. Output is compatible with standard tsconfig.json setups including resolveJsonModule: true, so you can drop interfaces straight into a Node or browser project without adjusting tsconfig options.
• Instant copy to clipboard. One click copies the full .ts type definitions so you can paste them directly into your editor, no download step required.
• Privacy-first, zero dependencies on external APIs. The entire json parser typescript logic runs in your browser. Unlike cloud tools that log your payloads, nothing here touches a server — critical when working with internal API shapes or customer data samples.

How to use the Json To Typescript

Paste your JSON, set a root type name if you want, then click Generate. Copy the output and drop it into your .ts file.

1. Paste your JSON. Copy any JSON object or array — an API response, a package.json typescript config block, a fixture file — and paste it into the input panel.
2. Set the root type name (optional). Type a name in the root type field, e.g. UserProfile or ApiResponse. Leave it blank and the tool defaults to Root.
3. Generate interfaces. Click Generate. The tool walks the JSON tree and emits typed interfaces. For example, { "id": 1, "name": "Ada" } becomes: ``ts interface Root { id: number; name: string; } ``
4. Copy and paste into your project. Hit Copy, then paste the interfaces into your TypeScript file. They're compatible with any standard tsconfig json example setup, including tsconfig node and tsconfig jsx projects.

Common use cases

• Typing third-party REST API responses. You hit an undocumented endpoint from a service in Sydney or Dublin and get back a large JSON blob. Paste it here, get typed interfaces, and stop using any in your fetch wrappers.
• Scaffolding types from database seed files. When your package.json scripts include seed data as JSON fixtures, use this tool to generate matching TypeScript interfaces before writing repository or service layer code.
• Working with tsconfig resolveJsonModule. If you import JSON directly via resolveJsonModule: true in your tsconfig.json, you still need explicit interfaces for function signatures. Generate them here and avoid implicit any errors.
• Onboarding to an unfamiliar codebase. Drop in an existing JSON config or API payload to quickly build a mental model of the data shape — faster than reading the docs, and the output gives you a working typescript json schema to reference. If you need to reformat that JSON first, the [JSON formatter](/en/json-formatter/) cleans it up before you paste.
• Converting OpenAPI example payloads. OpenAPI specs often include example JSON blocks. Paste them here to generate a first-pass TypeScript type, then refine with enums or branded types as needed. For projects that also use YAML configs, the [JSON ↔ YAML converter](/en/json-yaml-converter/) handles that step.

Frequently asked questions